Noise has become a major source of nuisance in great urban centers and even in the smallest villages, for example, those traversed by roads with high traffic density or situated in the vicinity of airports. The noise is much more apparent and objectionable at night when it can seriously disturb sleep.
It must be unfortunately concluded that current homes have not been conceived to assure an effective protection against noise. A better isolation of the openings in homes leads generally to a lack of ventilation which can be as unacceptable in certain cases as the perceived noise when the windows are open. Only in rare modern buildings which are well insulated and provided with a system of air conditioning can the nuisance due to noise be reduced to an acceptable level on the condition, of course, that the noise level of the air conditioning system is itself acceptable.